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Antimicrobial resistance is one of the major global health threats. Antimicrobial stewardship (AMS) has been set as a priority within international action plans to combat this issue. The region of Latin America and the Caribbean are recognized for their high antimicrobial resistance rates; nevertheless, a low number of studies describing implemented interventions for this topic have been published. This review aims to provide an overview of the status of AMS in our region, focusing on the main progress achieved and describing the different published efforts made by countries towards the implementation of antimicrobial stewardship programs (ASP). Common areas of intervention included were (a) education approaches, (b) antimicrobial guideline implementation and monitoring, (c) diagnostic stewardship, (d) technological tools: electronic clinical decision support systems in AMS, (e) pharmacy-driven protocols and collaborative practice agreements, and (f) economic impact. The search demonstrated the varied interventions implemented in diverse healthcare settings; the results accentuate their influence on antimicrobial consumption, antimicrobial resistance, clinical outcomes, and direct economic impact. The integration of multiple strategies within each hospital was highlighted as an essential key to ASP success. Even though the literature found demonstrated clear progress, there is still a special need for strengthening leadership from the top down, defining goals based on needs, and gaining support through policy and financing in LAC.

We report the presence of the mcr-1 gene among 880 Escherichia coli clinical isolates collected in 13 hospitals from 12 Colombian cities between 2016 and 2019. Seven (0.8%) isolates were colistin resistant (MIC ≥ 4 µg/mL). These colistin-resistant isolates were screened for the presence of the mcr-1 gene; five carried the gene. These five isolates were subjected to whole genome sequencing (WGS) to identify additional resistomes and their ST. In addition, antimicrobial susceptibility testing revealed that all E. coli isolates carrying mcr-1 were susceptible to third generation-cephalosporin and carbapenems, except one, which carried an extended-spectrum β-lactamase (CTX-M-55), along with the fosfomycin resistance encoding gene, fosA . WGS indicated that these isolates belonged to four distinct sequence types (ST58, ST46, ST393, and a newly described ST14315) and to phylogroups B1, A, and D. In this geographic region, the spread of mcr-1 in E. coli is low and has not been inserted into high-risk clones such as ST131, which has been present in the country longer.

Background: Ceftolozane/tazobactam (C/T) is a combination of an antipseudomonal oxyiminoaminothiazolyl cephalosporin with potent in vitro activity against Pseudomonas aeruginosa and tazobactam, a known β-lactamase inhibitor. The aim of this study was to evaluate the activity of C/T against clinical isolates of P. aeruginosa and Enterobacterales collected from five Latin American countries between 2016 and 2017, before its clinical use in Latin America, and to compare it with the activity of other available broad-spectrum antimicrobial agents., Methods: a total of 2760 clinical isolates (508 P. aeruginosa and 2252 Enterobacterales ) were consecutively collected from 20 hospitals and susceptibility to C/T and comparator agents was tested and interpreted following the current guidelines., Results: according to the CLSI breakpoints, 68.1% (346/508) of P. aeruginosa and 83.9% (1889/2252) of Enterobacterales isolates were susceptible to C/T. Overall, C/T demonstrated higher in vitro activity than currently available cephalosporins, piperacillin/tazobactam and carbapenems when tested against P. aeruginosa , and its performance in vitro was comparable to fosfomycin. When tested against Enterobacterales , it showed higher activity than cephalosporins and piperacillin/tazobactam, and similar activity to ertapenem., Conclusions: these results show that C/T is an active β-lactam agent against clinical isolates of P. aeruginosa and Enterobacterales .

Polymyxin resistance in Klebsiella pneumoniae has been attributed to mutations in mgrB , phoPQ , pmrAB , and crrAB and to the presence of mcr plasmid-mediated genes. Herein, we describe the molecular characteristics of 24 polymyxin- and carbapenem-resistant K. pneumoniae isolates recovered from six Colombian cities between 2009 and 2019. Minimum inhibitory concentrations (MICs) to polymyxin were confirmed by broth microdilution, and whole-genome sequencing was performed to determine sequence type, resistome, and mutations in the genes related to polymyxin resistance, as well the presence of mcr . The results showed high-level resistance to polymyxin (MICs ≥ 4 μg/mL). bla KPC-3 was present in the majority of isolates (17/24; 71%), followed by bla KPC-2 (6/24; 25%) and bla NDM-1 (1/24; 4%). Most isolates belonged to the CG258 (17/24; 71%) and presented amino acid substitutions in PmrB (22/24; 92%) and CrrB (15/24; 63%); mutations in mgrB occurred in only five isolates (21%). Additional mutations in pmrA , crrA , and phoPQ nor any of the mcr resistance genes were identified. In conclusion, we found clonal dissemination of polymyxin and carbapenem-resistant K. pneumoniae isolates in Colombia, mainly associated with CG258 and bla KPC-3 . Surveillance of this multidrug-resistant clone is warranted due to the limited therapeutic options for the treatment of carbapenem-resistant K. pneumoniae infections.

Background: The dissemination of the uropathogenic O25b-ST131 Escherichia coli clone constitutes a threat to public health. We aimed to determine the circulation of E. coli strains belonging to O25b:H4-B2-ST131 and the H 30-Rx epidemic subclone causing hospital and community-acquired urinary tract infections (UTI) in Colombia., Methods: Twenty-six nonduplicate, CTX-M group-1-producing isolates causing UTI in the hospital and community were selected for this study., Results: Twenty-two E. coli isolates harboring CTX-M-15, one CTX-M-3, and three CTX-M-55 were identified. Multilocus Sequence Typing (MLST) showed a variety of sequence types (STs), among which, ST131, ST405, and ST648 were reported as epidemic clones. All the E. coli ST131 sequences carried CTX-M-15, from which 80% belonged to the O25b:H4-B2 and H 30-Rx pandemic subclones and were associated with virulence factors iss , iha , and sat . E. coli isolates (23/26) were resistant to ciprofloxacin and associated with amino acid substitutions in quinolone resistance-determining regions (QRDR). We detected two carbapenem-resistant E. coli isolates, one coproducing CTX-M-15, KPC-2, and NDM-1 while the other presented mutations in ompC . Additionally, one isolate harbored the gene mcr-1 ., Conclusions: Our study revealed the circulation of the E. coli ST131, O25b:H4-B2- H 30-Rx subclone, harboring CTX-M-15, QRDR mutations, and other resistant genes. The association of the H 30-Rx subclone with sepsis and rapid dissemination warrants attention from the public health and infections control.

Background : High rates of resistance to third-generation cephalosporins and carbapenems in Enterobacterales have been reported in Latin America. Ceftazidime/avibactam (CZA) is the combination of a third-generation cephalosporin and a non-β-lactam β-lactamase inhibitor, which has shown activity against isolates producing class A, C and D β-lactamases. Herein, we evaluated the activity of CZA and comparators against clinical isolates of Enterobacterales in Latin America. Methods : The activity of CZA and comparators was evaluated against clinical isolates of Enterobacterales from Argentina, Brazil, Chile, Colombia and Mexico that were collected between January 2016 and October 2017. One specific phenotypic subset was evaluated. A carbapenem non-susceptible (CNS) phenotype was defined as any isolate displaying a minimum inhibitory concentration (MIC) ≥1 mg/L for ertapenem. Results : CZA was active against 95.8% of all isolates and 77.5% of CNS isolates. Fosfomycin (FOS) and tigecycline (TGC) were the second most active antibiotics with 93.4% of Enterobacterales being susceptible. Conclusions : The results of this study underline the potential therapeutic role of CZA in Latin America.